Fuel cells capable of power generation at a high efficiency even with a small size are being progressively developed as a key component of a power generation system for a distributed energy supply source. A supply system of hydrogen gas, which is a fuel necessary for power generation, is not sufficiently provided as a general infrastructure. Therefore, a reformer for generating hydrogen-containing gas using a raw material (hydrocarbon-based gas) supplied from an existing fossil raw material infrastructure such as, for example, city gas, propane gas or the like is provided with a fuel cell.
Hydrocarbon-based gas such as city gas, propane gas or the like which is supplied from an existing infrastructure usually contains an odorant such as a sulfur compound, for example, CH3SCH3 or (CH3)3CSH, at a volume concentration of about several ppm's. Such an odorant is added in order to detect a gas leak from a pipe or the like of the infrastructure line. However, a sulfur compound contained in such gas as an odorant poisons catalysts used in the reformer. Accordingly, in order to suppress the poisoning influence of sulfur on the catalyst, the sulfur compound needs to be removed from the raw material such as city gas, propane gas or the like before the raw material is supplied to the reformer.
Patent Document No. 1 proposes adsorbing a sulfur compound in the raw material by an adsorptive desulfurization section using a zeolite-based adsorptive removal agent in order to remove the sulfur compound from the raw material before the raw material is supplied to the reformer.
With an adsorptive desulfurization section using a zeolite-based adsorptive removal agent, the adsorbing capacity on a sulfur compound is small. In order to sufficiently suppress the poisoning influence of sulfur on the catalyst used in the reformer, the adsorptive desulfurization section needs to be exchanged every certain time period. For example, Patent Document No. 2 filed by the present Applicant describes using a detachable adsorptive desulfurization section in a fuel cell power generation system and proposes determining the time to exchange the adsorptive desulfurization section based on an accumulated amount of the raw material gas which has passed the section. Patent Document No. 3 proposes a method of networking a plurality of fuel cell power generation systems installed at houses and facilities to determine the time to exchange the adsorptive desulfurization section.    Patent Document No. 1: Japanese Laid-Open Patent Publication No. 2004-228016    Patent Document No. 2: Japanese Laid-Open Patent Publication No. 2006-8459    Patent Document No. 3: Japanese Laid-Open Patent Publication No. 2006-278120